I'm having trouble installing CentOS-7 on my HP MicroServer. I've tried with KDE LiveCD and Netinstall (both on USB sticks), and now I'm going to try with the DVD ISO. But I want to be quite sure I can return to CentOS-6.5 if things go wrong, so I'm wondering what precisely I need to copy (eg the MBR and a bit more) so that I could get back to things as they were. Is this documented anywhere? Actually, both failed installations did give a boot menu including the old 6.5 system, but I'm afraid sometime this might not work, and I will be cut off from the world. Incidentally, the "Repair" option on the netinstall system was not as useful as I expected, or perhaps I don't know how to use it properly. It entered the new CentOS-7 system OK on chroot-ing, even mounting other partitions listed in /etc/fstab . And I was able to bring up the interfaces with "service network restart". But although I ran grub2-install , this did not help matters. Is there anything else one can do after chrooting into a system? Eg, can one boot the system in any way? Any advice or suggestions gratefully received. -- Timothy Murphy e-mail: gayleard /at/ eircom.net School of Mathematics, Trinity College, Dublin 2, Ireland